Low interfacial tension surfactants for petroleum applications

ABSTRACT

The invention relates to a class of novel surfactants that have utility in the recovery and/or extraction of oil.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/958,890, filed Dec. 2, 2010, which claims the benefit of U.S.Provisional Application No. 61/285,385 filed Dec. 10, 2009. The entireteachings of the above applications are incorporated herein byreference.

FIELD OF THE APPLICATION

The application relates generally to surfactants useful for petroleumapplications.

BACKGROUND

A number of problems in the petroleum industry derive from theviscosity, surface tension, hydrophobicity and density of crude oil.Heavy crude oil in particular, having an API gravity of less than 20degrees, is difficult to transport due to its viscosity, and isdifficult to remove from surfaces to which it has adsorbed, due to itshydrophobicity and immiscibility with water. Extra-heavy crude oil orbitumen, having an API gravity of less than 10 degrees, is heavier thanwater, so that it can sink to the bottom of a water formation, causingsubsurface contamination.

The properties of crude oil contribute to the limitations of oilrecovery from traditional oil fields. Conservative estimates suggestthat 30% of the technically recoverable oil in U.S. oil fields isinaccessible due to the adsorption of the residual oil to porousgeologies. Technologies to unlock the oil in these so-called “dead”wells presently involve the use of hot water injections with expensivesurfactants, chemistries that are applied to overcome the hydrophobicityof the adsorbed oil so that it can be mobilized.

The properties of crude oil also contribute to the difficulty ofenvironmental remediation following, for example, an oil spill onto abody of water. The high interfacial tension causes the oil to float onthe water and adhere to plants, animals and soil. As the aromaticconstituents of the oil evaporate, the heavier residues can sink,contaminating the subsurface structures. Current treatment of spilledoil on water surfaces relies on time-consuming and expensive biologicaldegradation of the oil. Thick, adherent crude oil cause environmentalproblems in the oil fields as well. Oil deposits attached to vehiclesand equipment must be cleansed with jets of hot water and caustics.

The viscosity of heavy crude oil makes the substance difficult andexpensive to transport to upgrading facilities. Because of itsviscosity, a significant amount of energy is required to pump it throughpipelines to a refinery. Furthermore, the viscosity affects the speed atwhich the heavy crude oil can be pumped, decreasing the overallproductivity of an oil field. Exploiting certain oil fields or other oildeposits may be economically unfeasible to develop at present because ofthe transportation-related costs.

Crude oil, as it is produced, is typically associated with connate waterthat can form a stable emulsion with the oil in multiple phases,including solid-in-oil dispersions, water-in-oil emulsions, andoil-in-water-in-oil emulsions. Certain hydrocarbon molecules found inheavy crude oils can act as emulsifiers to stabilize the various speciesof water plus oil emulsions. As an example, asphaltenes and highnaphthenic acids, along with submicron sized solid particles such assilica, clay or other minerals, can stabilize emulsions such aswater-in-oil emulsions where the heavy crude oil fluid comprises thecontinuous phase. Asphaltenes are high-molecular weight, complexaromatic ring structures that can also contain oxygen, nitrogen, sulfuror heavy metals. As polar molecules, they tend to bond to chargedsurfaces, especially clays, leading to formation plugging and oilwetting of formations. Asphaltenes tend to be colloidally dispersed incrude oils, stabilized by oil resins.

Asphaltenes, paraffinic waxes, resins and other high-molecular-weightcomponents of heavy crude exist in a polydisperse balance within theheavy crude fluid. A change in the temperature, pressure or compositioncan destabilize the polydisperse crude oil. Then the heavy and/or polarfractions can separate from the oil mixture into steric colloids,micelles, a separate liquid phase, and/or into a solid precipitate. Theasphaltene micelles can be destabilized during well treatments, e.g.,acidizing or condensate treatments, leading to asphaltene precipitation.Asphaltene precipitation causes problems all along the crude oilprocess. Asphaltene precipitation becomes increasingly problematic whencrude oil is processed, transported, or stored at cooler temperatures,because the heavier components of crude oil (e.g., asphaltenes andnaphthenic acids) that remain dissolved in the heavy crude under hightemperatures and pressures are no longer supported in that state as theconditions change. When the heavy crude oil cools to ambient atmospherictemperatures, these components can precipitate out of the crude oilitself and lodge at the bottom of a storage vessel or tank to form aviscous, tarry sludge. These components also become available asemulsifying agents to sustain water-in-oil emulsions. The emulsion layerhas a higher density than light crude, so that it tends to sink to thebottom of storage vessels along with the heavy oil components andassociated clay/mineral solids, contributing to the buildup of oilsludge, a thick waste material formed from the various depositssedimenting out from a crude oil mixture.

As mentioned previously, sludge forms when heavier components of crudeoil separate from the liquid hydrocarbon fractions by gravity and sinkto the bottom of the vessel. Components of the sludge can include usablehydrocarbons along with the aforesaid entrained water as a water-in-oilemulsion, along with a multitude or organic and inorganic components andcontaminants. As the heavier elements in the stored oil continue tomigrate to the vessel bottom, the sludge becomes increasingly viscousover time. Any given storage vessel can thus contain a significantamount of sludge, which can diminish storage space for useful crude oiland which can otherwise reduce the efficiency of storage tank operation.Sludge may also require removal if the storage vessel is to bemaintained, repaired or inspected.

Many approaches have been proposed for preventing the formation ofsludge in oil storage vessels such as oil tanks and oil tankers, and forremoving sludges and oily sediments that have formed. In particular, itis desirable to recapture valuable hydrocarbons from the sludge as partof the removal process. The two dominant systems for sludge removal aresurfactant-based approaches and solvent-based approaches. Insurfactant-based systems, aqueous solutions are used to treat the sludgeand coalesce the water droplets emulsified within the oil matrix. Theparticular surfactant is designed to overwhelm the surface energy thatis created by the asphaltene/naphthenic acid molecules and return theaqueous portion to a more-native interfacial tension with organics.Current surfactant additives have been shown effective but havecommercial limitations because of either high dosage requirements orineffective solids interactions. Solvent systems typically use a mixtureof known aromatic and aliphatic-based organics to decrease the viscosityof the heavier oil fractions and cause phase separation. Issues of costand toxicity, however, have been raised with the use of solvent-basedapproaches.

The development of a technology that can provide emulsion and favorabletransport properties while maintaining the ability to demulsify ondemand, all under variable conditions of salinity, temperature, pH,etc., remains unmet in the art. Such a technology would have widereaching impact across the oilfield chemical sector in applications suchas those mentioned above, particularly if the material could beinexpensively produced and could be applied to a variety of oil types.

Additional uses for a surfactant technology in the oil industry arisefrom the problems posed by oil well drilling. When drilling oil or gaswells, a drilling fluid, referred to as a “drilling mud,” is circulateddownwardly through a pipe to reach the drill bit, lubricating it andcarrying away the cuttings from the drilling process. The clean drillingmud is injected through a series of pipes called the drill string toreach the bit, and then flows back up to the surface in the annular areabetween the drill string and the inside of the wellbore carrying thecuttings and other particulate matter. The drilling mud can bewater-based or oil-based. Oil-based drilling fluids include as theirbase material any of a number of natural or synthetic oils, includingpetroleum fractions, synthetic compounds, blends of natural andsynthetic oils, along with a variety of performance-enhancing additives.Following drilling, the wellbore annulus must be cleaned to removedrilling fluids, gelled drilling fluid, residual additives from drillingfluids, and the like. One cleaning process can take place before thecasing and cementing operations are done, and another cleaning processis done after the casing is installed. The casing must be cleaned to awater-wet condition with no oil sheen. Oil-based drilling fluids,especially synthetic based muds (SBMs), are particularly difficult toremove from the surfaces they contact. These oil-based fluids can forminvert emulsions upon contact with water, where the continuous phase ispredominantly organic, and the discontinuous phase is aqueous. Thisemulsion will tenaciously coat any surface that it contacts, leading tooil wetting of borehole surfaces, casing surfaces, and the surfaces ofother equipment that it contacts.

Wellbore cleaning can involve the use of a sequence of fluids, eachhaving a specific purpose. In designing the sequence for the cleaningprocess, formulations are selected that give maximum performance whileusing minimum amounts of material. Also, the fluids must be chemicallyand physically compatible, so that an earlier one does not interferewith the function of subsequent ones. Cleaning operations must beconducted carefully, so that the clay components of the drilling mudresidue do not come into contact with water, thereby forming a thickpaste that adds to the difficulty of removal. There remains a need inthe art, however, for a cleaning system that is effective and efficientin removing drilling mud films and residua from wellbore surfaces. Thisneed is exacerbated by the prevalence of SBMs, which produceharder-to-remove films. There is also a need for a cleaning system thatrequires less fluid volume than those systems presently in use. Inaddition, there is a need for a cleaning system that does not require orproduce hazardous materials.

SUMMARY

The invention relates to the discovery to surfactant compounds withutility in recovering or extracting oil, such as fossil fuels.

Accordingly, in some embodiments, the invention relates to a compoundhaving the Formula (I):

wherein A is an alkyl, alkenyl, alkadienyl, alkynyl, cycloalkyl, orcycloalkenyl, each optionally substituted;p is 1 or 2; preferably 2;m and n are independently 0, 1, 2, 3, 4, or 5;each of G₁ and G₂ are independently absent, O, S, NR₂, (CO)O, O(CO), CO,CONR₂, or NR₂CO;each R₂ is independently H or a lower alkyl;G₃ is absent, (CH₂)_(q) or G₁;q is 1, 2, 3, 4 or 5;R is a hydrophilic group; andR₁ is a saturated or unsaturated hydrophobic aliphatic group. In certainaspects, m is 1 or 2 and n is 0 or 1. In some embodiments, at least oneof G₁ and G₂ are present.

In some embodiments, the invention is compound having the Formula (Ia):

wherein t is 0 or 1;G₄ is O or NH; and A and R₁ as defined above.

In an additional embodiment, the invention is directed to a compound ofFormula (II):

wherein D is an aliphatic polymer;p is 1 or 2; preferably 2;m and n are independently 0, 1, 2, 3, 4, or 5;each of G₁ and G₂ are independently absent, O, S, NR₂, (CO)O, O(CO), CO,CONR₂, or NR₂CO;each R₂ is independently H or a lower alkyl;G₃ is absent, (CH₂)_(q) or G₁;q is 1, 2, 3, 4 or 5;R is a hydrophilic group; andR₁ is a saturated or unsaturated hydrophobic aliphatic group.

In certain embodiments, the invention encompasses a compound having theFormula (IIa);

wherein t is 0 or 1;G₄ is O or NH; and D and R₁ are as defined above.

In an additional embodiment, the invention relates to a compound ofFormula III:

wherein E is alkyl, alkenyl, alkadienyl, alkynyl, cycloalkyl,cycloalkenyl, aryl and heteroaryl;G₅ is CONH;D₂ is a hydrophilic aliphatic polymer; andp is 1 or 2.

In yet another aspect, the invention encompasses a compound having theFormula (IV):

wherein D₂ is a hydrophilic aliphatic polymer;wherein each J is independently selected from the group consisting ofhydrogen and the Fragment (A) having the structure shown below;

wherein E is a hydrophobic group selected from the group consisting ofalkyl, alkenyl, alkadienyl, alkynyl, cycloalkyl, cycloalkenyl, aryl andheteroaryl; and wherein at least one J is the Fragment (A).

The invention also encompasses a compound having the Formula (V):

wherein D₂ is a hydrophilic aliphatic polymer;each J is independently selected from the group consisting of H and theFragment (A):

wherein E is a hydrophobic group selected from the group consisting ofalkyl, alkenyl, alkadienyl, alkynyl, cycloalkyl, cycloalkenyl, aryl andheteroaryl;and wherein at least two of J are Fragment (A).

The invention also relates to methods for extracting oil from an oilmixture comprising:

(a) adding a compound of any one of Formula (I), Formula (Ia), Formula(II), Formula (IIa), Formula (III), Formula (IV) and Formula (V), or acombination of any of thereof, to an oil mixture, and

(b) collecting the oil.

An oil mixture is a mixture comprising oil and at least one othercomponent. The oil mixture can comprise oil sands, waterborne oil slicksor oil deposits. Further, the methods of the invention can comprise theadditional steps of adding water or transporting the mixture via apipeline. In another embodiment, the compounds and compositions of theinvention can be used in methods of degreasing machinery, such as thoseused in oil or bitumen production.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

FIG. 1 shows comparison photographs of phase separation.

FIG. 2 shows comparison photographs of solutions prepared at neutral andacidic pH.

DETAILED DESCRIPTION

General Formulations

Disclosed herein are compositions, systems and methods related toultra-low interfacial tension (“IFT”) surfactants for applications inthe petroleum industry. In certain embodiments, the present disclosureis based on the discovery that multiple aliphatic-based functionalitiescan be incorporated onto a single surfactant molecule. This molecule caninclude functionality that allows it to be either surface-active orsurface-inactive by adjusting or “tuning” the surfactant by means of anadjustment of a parameter such as temperature or pH. Preferably, theapplication of a single-molecule, switchable surfactant system isprepared in aqueous solution. Suitable surfactant solutions forapplication in enhanced oil recovery will also display very lowinterfacial tension values with both crude oil as well as organics withaliphatic and aromatic character. Additionally, surfactant solutionsexhibiting only pH switchability will remain in solution at elevatedtemperatures, so that they can be inserted into underground wells, wheretemperatures may range between 70-100° C.

For such applications as enhanced oil recovery, the ability todeactivate a surfactant (i.e., “turn it off”) would enable the userfirst to create an emulsion of the petroleum to be recovered, then totransport the oil in an emulsified state, then to easily separate theoil from the emulsion when it has reached its desired destination.Controlling the phase state of an oil deposit could potentially be auseful tool in recovering difficult to access, yet desirable, sources ofoil.

In one embodiment, compositions of particular use in these systems andmethods can include at least one compound of the Formula (I), Formula(Ia), Formula (II), Formula (IIa), Formula (III), Formula (IV) orFormula (V) as described above.

In some aspects of the invention, the compound has the Formula (I),(Ia), (II) or (IIa). The invention encompasses compounds having theFormula (I) or Formula (Ia), wherein A is an alkyl (e.g., a C₃-C₈ alkyl)or cycloalkyl, each optionally substituted. In another embodiment, A isan alkyl-substituted cyclopentyl or cyclohexyl. Examples ofalkyl-substituted cyclohexyl is propylcyclohexyl and ethylcyclohexyl. Inadditional aspects, the compound has the Formula (I), wherein G₁ isselected from the group consisting of O, S, NR₂, C(O)O, OC(O), C(O),C(O)NR₂ and NR₂C(O). In yet additional aspects, the compound has theFormula (I), wherein G₁ is selected from the group consisting of C(O)O,OC(O), C(O), C(O)NR₂ and NR₂C(O). In yet further aspects, G₁ is selectedfrom C(O)O and C(O)NR₂. In additional aspects, the compound has theFormula (I) wherein p is 1. In yet additional aspects, the compound hasthe Formula (I) wherein p is 2. In a further aspect, the invention is acompound of Formula (I) wherein m is 1 or 2. In yet additional aspects,the invention is a compound of Formula (I), wherein n is 0 or 1. In yetanother aspect, the invention is a compound of Formula (I), wherein R isC(O)OH. In a further aspect, the invention is a compound of Formula (I),wherein R₁ is selected from the group consisting of C₅-C₂₀ alkyl, C₅-C₂₀alkenyl, and C₅-C₂₀ alkadienyl.

In other embodiments, the compound has the Formula (II) or (IIa),wherein D is selected from the group consisting of polyethylene glycol,poly(ethylene glycol)/poly(propylene glycol) copolymers, polyethyleneglycol methyl ether, polyetheramine and ethylene oxide/propylene oxideblock copolymer. In additional aspects, the compound has the Formula(II), wherein p is 1. In a further aspect, the compound has the Formula(II), wherein p is 2. In yet an additional aspect, the compound has theFormula (II), wherein m is 1 or 2, or n is independently 0 or 1, or acombination thereof. The invention also includes the compound of Formula(II), wherein each G₁ is independently OC(O), C(O)O, C(O), C(O)NR₂ orNR₂C(O). In an additional aspect, the compound has the Formula (II)wherein G₂ is absent. In a further aspect, the compound has the Formula(II) wherein R is C(O)OH.

As described above, compounds of Formula (I), (Ia), (II) and (IIa)comprise a hydrophilic portion (substituent R) and a hydrophobicaliphatic group (substituent R₁). In some embodiments, the aliphaticgroups include saturated or unsaturated carbon chains, preferablybetween five and twenty units in length, or five and eighteen units inlength, or eight and twenty units in length, or hydrogen. The carbonchains can optionally be unsaturated and, when present, reside anywherealong the carbon chain. The hydrophilic portion of the inventivecompounds can comprise one or more hydrophilic groups or substituents.Hydrophilic portions or groups can be an ionizable groups, including,for example, amines and carboxylic acids. In certain aspects of theinvention, the hydrophilic group is C(O)OH. Hydrophilic groups alsoinclude hydrophilic polymers, including, but not limited to,polyalkylamine, poly(ethylene glycol) or poly(ethyleneglycol)/poly(propylene glycol) copolymers. Nonionic hydrophilicmaterials such as polyalkylamine, poly(ethylene glycol) or poly(ethyleneglycol)/poly(propylene glycol) copolymers can be used to increasehydrophilicity or aid stability in salt solutions.

In some embodiments, the surfactant compound has the Formula (III). Incertain aspects, D₂ is a polymer or copolymer containing ether groups.The invention also encompasses a method for the preparation of acompound having the Formula (III) comprising reacting an aliphatic oraromatic diacid with a polyetheramine. In an additional embodiment, thecompound has the Formula (III), wherein E is C₁-C₆ alkyl.

In an additional embodiment, the surfactant compound has the Formula(IV) or Formula (V) as described above, wherein D₂ is a polyether. Incertain aspects, E is a C₅-C₂₀ alkyl, C₅-C₂₀ alkadienyl or C₅-C₂₀alkenyl.

The invention also is directed to methods for the preparation of acompound having Formula (IV) or Formula (V) comprising reacting anamino-containing polyether with an epoxy-containing compound. An exampleof an amino-containing polyether is a polyetheramine. Non-limitingexamples of epoxy-containing compounds are styrene oxide,2,3-diphenyloxirane, phenyl glycidyl ether, 1-naphthyl 2-oxiranylmethylether, and poly[(o-cresyl glycidyl ether)-co-formaldehyde.

In certain aspects, a lower alkyl is a C₁-C₁₀ alkyl, C₁-C₆ alkyl, orC₁-C₄ alkyl

The compounds described herein can be used as surfactants. Inembodiments, these compounds can demonstrate switchable behavior underconditions where pH and/or temperature is varied.

Switchability

In embodiments, the inventive surfactants, such as a compound of Formula(I), (Ia), (II), (IIa), (III), (IV) or (V), can demonstrate switchablebehavior based on pH, where the surfactant is capable of sustaining anemulsion at a higher pH, but loses its emulsification properties at alower pH. In embodiments, pH switchable surfactants can comprise anionizable group and a hydrophobic portion, or an ionizable portion and ahydrophilic and a hydrophobic portion. The ionizable group on thesurfactant reacts to changes in pH that impact its emulsificationproperties. For example, with a decrease in pH, the ionizable group willbe in the protonated form and the surfactant molecule will lose itssolubility in water solution, thereby losing its emulsificationproperties. Conversely, if the pH increases, the ionizable group will bein the ionic form and the surfactant molecule will increase itssolubility in water solution, thus being capable of sustaining emulsionsof oil in water. This behavior is reversible because no functionalgroups are cleaved in the process. Non-limiting examples of surfactantsdemonstrating this behavior include surfactants prepared in accordancewith Examples 1, 2 and 3 shown below.

In embodiments, surfactants can demonstrate switchable behavior based onchanges in temperature, whereby they are able to stabilize emulsions attemperatures below their cloud points but lose their emulsificationproperties at temperatures above their cloud points. In embodiments,temperature switchable surfactants will have a hydrophobic portion and ahydrophilic portion mainly containing, for example, ethoxylated groups.Such surfactants can display solubility in water solutions attemperatures below the cloud point and will be able to emulsify oil inwater. However, upon increasing the temperature above the cloud point,the surfactants will lose solubility in water solutions and will losetheir emulsification properties. The behavior is reversible because nofunctional groups are cleaved in the process. Non-limiting examples ofsurfactants demonstrating this behavior are those prepared in accordancewith Examples 9, 10, 11 and 13.

In embodiments, surfactants can demonstrate switchable behavior based onchanges in temperature and pH. There are trigger points foremulsification capability that are determined by pH and by temperature.Non-limiting examples of such surfactants are those prepared inaccordance with Examples 4, 5, 6 and 7 below.

In certain embodiments, temperature switchable behavior can be elicitedin compounds having ether groups. For example, PEG orhydroxyl-terminated ethers such as PPO and PEO (e.g., Pluronics) can bereacted with anhydrides such as alkene succinic anhydride (8, 9, 12units), and styrene maleic anhydride copolymers.

In other aspects of the invention, the hydrophilic portion of thesurfactant compounds of the invention include one or more polymers orcopolymers containing ether groups. These polymers impart the compoundswith a cloud point. The compounds will display solubility in water attemperatures below the cloud point and, as a consequence, are able toemulsify oil. However, upon increasing the temperature over the cloudpoint, the compounds become less soluble in water and show a decrease inemulsification properties. It is believed that this behavior isreversible because no functional groups are cleaved in the process. Somenon-limiting examples of these kinds of compounds can be obtained byreacting:

(i) Amino (primary or secondary)-containing polyethers with epoxycompounds. Examples of amino-containing compounds are: polyetheramines,such as JEFFAMINES® from Huntsman, and other PEG and PPO/PEG containingprimary, secondary amines. Examples of epoxy compounds include arylglycidyl ether, such as: styrene oxide, 2,3-diphenyloxirane, phenylglycidyl ether, 1-naphthyl 2-oxiranylmethyl ether, and poly[(o-cresylglycidyl ether)-co-formaldehyde;

(ii) Acid groups with amines or alcohols. Examples include reactingaromatic diacids with a polyether containing (primary or secondary)amine or hydroxy units. Another embodiment is the reaction of apolyethylene glycol-diacid terminated with and aromatic amine oralcohol;

(iii) Copolymerizing monomers that can form polymers with LCST such asN-vinylcaprolactam, isopropyl acrylamide or diethylacrylamide withacrylic acid, followed by reacting the acid with a alcohol or aminegroups, preferably the alcohol or amine will be slightly hydrophobic(hexyl alcohol, hexyl amine, octyl alcohol, octyl amine, phenethylalcohol, etc.).

In some aspects of the invention, the hydrophilic portion of compoundsof the invention is a combination of (i) one or more copolymerscontaining ether groups and (ii) one or more ionizable carboxylic acidgroups. In this case, the obtained compound has emulsificationcapabilities that are triggered by a change in pH or temperature. Belowa specific pH, the surfactant compound has emulsification propertiesunder certain temperature conditions. However, above that pH, thetemperature at which the surfactant has emulsification propertiesincreases. The surfactants are thus tunable based on changes in pH ortemperature.

Exemplary surfactants can be synthesized by reacting:

(i) PEG and PPO/PEG (hydroxyl terminated) with aromatic anhydrides.Examples of PEG and PPO/PEG are the PLURONICS®. Examples of aromaticanhydrides are phenyl succinic anhydride;

(ii) Copolymerizing monomers that can form polymers with LCST such asN-vinylcaprolactam, isopropyl acrylamide or diethylacrylamide withacrylic acid followed by reacting a fraction of the acid with a alcoholor amine groups, preferably slightly hydrophobic (hexyl alcohol, hexylamine, octyl alcohol, octyl amine, Phenethyl alcohol, etc.).

Applications

Environmental Remediation

By taking advantage of the low IFT behavior of the surfactant compoundsdisclosed herein, such surfactants can be suitable for applicationswhere undesired petroleum products pose an environmental problem. Oilcleanup using surfactants may be required for two different types ofcontamination. First, as an oil slick dispersant, the surfactant familycan be used on waterborne slicks, acting as a dispersing agent. It willact to disperse the oil into the water body itself and encouragebiodegradation through natural decomposition means. Additionally, asolution of surfactant can be used to remove physiosorbed crude orrefined oils from inorganic rocks, sand, or other substrates as anemulsion.

Oil Sands Extraction

Oil sands comprise heavy petroleum products coating sand and clay, anassemblage that is similar to certain artificial composites that areformed during a man-made oil spill, as described above. The surfactantcompounds and compositions thereof described herein may be useful forextracting bitumen from the other components of the tar sands material.Currently, mined oil sands are extracted using hot water, a process thatcauses the less dense bitumen to flow off the sand and float to thesurface of a settling tank. This so-called “primary froth” iscontaminated with various materials derived from the mined products(solid particles, clay, and sand). Current froth treatment utilizesnaphtha, a valuable fraction of purified petroleum, to dilute thebitumen and decrease the viscosity to the point of flowability. Thisallows solids and water to be removed by settling and centrifugationmethods. By using an aqueous solution of surfactant as the dilutionmedium instead of naphtha, the latter solvent can be replaced with waterand surfactant, thus decreasing the cost of purifying the froth.Additionally, when the surfactant-diluted bitumen is recovered from thewater, the hydrophilic portions associated with the froth (clay, water,salts) will preferentially partition to the water phase and be separablefrom the bitumen.

Use of the inventive surfactants in accordance with these systems andmethods may further be applied to other aspects of the extractionprocess, for example in the oil sands strip mining or in-situoperations, where the ability to emulsify the petroleum component of theoil sands ore may enhance the efficiency or economy of separating thebitumen from the insoluble byproducts.

Oil Field Transport Emulsions

Transporting petroleum precursors for further processing is a necessary,though expensive, part of obtaining usable crude oil. When petroleum isobtained as a heavy crude, it needs to be transported to an upgradingfacility for conversion to useful petroleum products. Typically,pipeline transport is the most economical means to accomplish this. Whenoil sands are used as precursors in the production of synthetic crudeoil, they are transported for further processing after extraction andfroth treatment through pipelines as a naphtha-diluted bitumen so thatthey can undergo further upgrading processes, including cracking andcoking, amongst other standard refining operations. For these types ofapplications in the petroleum and tar sands industries, the heavy oil oroil precursor materials (respectively) may be transported throughpipelines as oil-in-water mixtures or emulsions. It is understood thatmore viscous matter being sent through pipelines has a greaterresistance to flow and consequently requires more energy to move anequivalent distance. Hence, decreasing the viscosity of the flowablematter decreases the amount of pumping energy required, and potentiallyimproves the transit time and the productivity of the overall process.Mixing water with crude oil or bitumen can decrease the viscosity ofthese latter substances towards the viscosity of water, but only if awater-continuous emulsion is created. The surfactants described hereincan compatibilize oil and water into an emulsion that can be pumped withgreatly decreased energy requirements and/or increase the throughput ofcrude oil or oil precursors to their destinations.

Auxiliary Petroleum Applications

There also exist many other opportunities in the oilfield chemicalsector for degreasing applications, as can be accomplished with thesystems and methods disclosed herein. Periodically, machinery used inoil and bitumen production must be cleaned for maintenance andperformance reasons. With petroleum production heading towards heaviercrude reserves, the need for an effective degreaser becomes even moreacute: exposure to heavier crude oils results in thicker, more adherentoil residues that must be removed during the cleaning/degreasingprocesses. The surfactants described herein can be an active ingredientin an industrial degreasing formulation for these purposes.

Enhanced Oil Recovery (EOR)

Tertiary oil recovery, also known as “enhanced” or “improved” oilrecovery, makes use of low IFT polymers to produce oil from wells thathave stopped producing of their own accord. Injection of a low IFTsurfactant into one of these less productive wells can stimulateproduction from the residual oil left adhered to the surface of porousrocks. The compounds described herein are useful as low IFT surfactantsfor EOR.

Desalting

Desalting refers to the process of removing salts from oil, making theoil more suitable for further refining. Salts, including magnesiumchloride, sodium chloride and calcium chloride can be found in crudeoil. If allowed to remain in the crude oil during the refineryoperation, the salts can dissociate and the chloride ion can ionize toform hydrochloric acid, which, along with various organic acids found incrude oil, contributes to corrosion in refinery equipment. In addition,other metal salts (e.g., potassium, nickel, vanadium, copper, iron andzinc) can be found in the crude oil, also contributing to fouling of theequipment and end-product degradation. Crude oil also containsemulsified water, which contains dissolved salts.

Desalting crude oil takes advantage of the fact that the salts dissolvein a water phase, which is separable from the oil phase. Crude oilnaturally contains water in emulsion, as mentioned above. For certaintechniques of desalting, additional water may be added to the oil (e.g.,in an amount between 5-10% by volume of crude) so that the impuritiescan further dissolve in the water. The water-in-oil emulsion can bebroken with the assistance of emulsion-breaking chemicals and/or byexposing the emulsion to an electrical field that polarizes the waterphase, so that the water phase bearing the impurities separates from thepetroleum phase. Ethoxylated nonylphenols are a class of nonionicsurfactants that have been used for desalting crude oil according tothese principles.

The surfactant compounds disclosed herein can facilitate thedemulsification of the water-in-oil emulsion, so that the oil phaseseparates from the water phase, with the water phase carrying thesoluble impurities (i.e., the salts). In embodiments, the hydrophilicportion of the surfactant compound can include one or more ionizablecarboxylic acid groups that can be ionized at a basic pH (e.g., >8) toproduce an emulsion-sustaining material. To destabilize the emulsion,acid may be added, removing the charge stabilization and allowing thetwo phases to segregate from each other.

Sludge and Tank Bottoms Clean-up

In accordance with these systems and methods, an aqueous surfactantsolution comprising an amphiphilic surfactant can be used to emulsifyheavy crude oil components that have settled as a sludge at the bottomof the oil containment vessel. Such a surfactant can be injected intothe sludge, thereby forming an oil-in-water emulsion comprising theheavy crude oil components of the sludge, which emulsion can then beremoved from the oil containment vessel, thereby desludging it. Inembodiments, the sludge to be treated comprises an oil-contaminatedsediment that was created by accidental discharge of hydrocarbons ontothe ground or a body of water. In embodiments, the sludge to be treatedcomprises asphaltenes, or it comprises a water-in-oil emulsion.

In embodiments, the aqueous surfactant includes a switchable, “smart”surfactant, which can be injected as an aqueous solution into an oilstorage vessel to emulsify the heavy oil sludge into the water phasewith minimal agitation. Establishing water as the continuous phase ofthe emulsion for the sludge can decrease the sludge viscosity so that itcan be pumped out of the storage vessel into an alternate containmentsystem. For example, the sludge-in-water emulsion can be directed to adistinct separation vessel, where the emulsion can then be broken,yielding a phase-separate two-component system comprised of crude oilfractions suitable for further refining and recovered water suitable forreuse in similar or other projects.

In embodiments, several steps will be required for the surfactantsystem. First, the surfactant will be injected into the heavy oil sludge(including the rag layer), so that the surfactant can destabilize theheavy oil-water interface to invert the emulsion into the water phase.In this initial phase, an amphiphilic, water-soluble polymer can be usedthat is effective at low concentrations. After this is accomplished, theresulting water emulsion can be removed from the subject vessel andrelocated, for example to a separation vessel. This may take place as aseparate step after the first step has been completed. In otherembodiments, however, this can take place during the first step. Forexample, the water emulsion can be siphoned off as it is formed. As afinal step, the water emulsion containing the stabilized oil dropletscan be demulsified. A change in the conditions of the water emulsion canchange the conformation of the surfactant, so that it breaks into anoil-soluble component and a water-soluble component. The oil-solublecomponent thus demulsifies the heavy oil droplets, while thewater-soluble component remains in the water phase. Surfactant moleculescan be designed so that the water-soluble byproduct is non-toxic andenvironmentally safe. The emulsification and/or separation processesmight be carried out at temperatures above ambient, to facilitate flowand emulsification or to cause switching of the surfactant properties.

In embodiments, a surfactant in accordance with these formulations andmethods can be formulated as a polymer that can emulsify the heavycrudes, but can decompose into one or more oligomers capable ofeffecting demulsification. Oligomers suitable for demulsifying caninclude: polyethylene oxide/polypropylene oxide copolymers, celluloseesters, polyethylene/ethylene oxide copolymers, ethoxylatednonylphenols, and the like. In embodiments, a random linear copolymercan act as the emulsifying agent. Such a copolymer can contain regionsof ionic charge, such as a quaternary amine or sulfonate, that would beresistant to the high-salt environment in the sludge. To create thesurfactant effect, the copolymer could further contain nonionic regionshaving hydrophobicity, such as polycarbonate, polystyrene or styrenemaleic anhydride. In the copolymer, a demulsifying oligomer (as setforth above) can be covalently attached to the nonionic hydrophobicregions. As a first step using these formulations, the sludge would beemulsified using the surfactants to form an oil-in-water emulsion. Theemulsion could then be pumped from the subject tank or other vessel to asuitable separation vessel. Heat could be optionally added. In theseparation vessel, the pH could be altered so that the covalent linkageholding the demulsifying moieties in place would be broken. If thecovalent bond is a weak one (e.g., an ester bond), it may be altered byadding heat only. For other covalent linkages (e.g., ethers and amides),alkali may need to be added to the emulsion. With the release of thedemulsifying agent from its attachment to the polymer, phase separationof oil and water would occur. Water and oil could then be directed forfurther processing as separate fluid streams.

Wellbore Cleaning

Disclosed herein are compounds and methods that have utility in cleaningwellbores and the like with a multipurpose water-based formulation thatcan remove films left behind from the use of synthetic base muds, and atthe same time leave the wellbore surface in a hydrophilic state.Advantageously, the disclosed formulations can minimize volumes ofcleaning materials utilized for wellbore cleanout, reduce the amount ofwaste material produced and offer tailored formulations for specificfilms left by different drilling muds. The hydrophilic regions of thesurfactant compounds disclose herein can attract aqueous fluids to washaway or break up the oil and the hydrophobic portion can be designed tohave high oil affinity.

Contaminated Cuttings

During the drilling process, cuttings are formed that are contaminatedwith oil. In many situations, they are considered hazardous wastebecause of their oil content, whether from oil-based drilling fluid orfrom formation-produced oil. Disposal of these contaminated cuttings isspecialized and expensive, because of their hazardous waste status. Inembodiments, cuttings generated during the drilling operations can becleaned using surfactants disclosed herein. Cleaning the cuttings byremoving the oil may reduce their hazard burden. The use of switchablesurfactants for cleaning cuttings is especially advantageous because theemulsion can be demulsified in a manner that minimizes the contaminatedwastewater produced and allows recovery of oil.

The invention is illustrated by the following examples which are notmeant to be limiting in any way.

EXAMPLES Materials

All materials were purchased from Aldrich except those listed below:

PLURONIC® L64, L35 and L31 were obtained from BASF Corporation, FlorhamPark, N.J. 07932, USA.

JEFFAMINE® ED-900, M-1000, ED-2003, ED-600 were obtained from HUNTSMAN,Austin, Tex. 78752, USA,

Eka SA 210: EKA Chemicals, Inc., Marietta, Ga. 30062, USA.

Example 1 Reaction Between Alkenylsuccinic Anhydride and AliphaticAlcohol

A reactor was charged with 1,3-butanediol (0.64 g, 7.14 mmol) (Aldrich)and Eka SA 210 brand alkylated succinic anhydride (5 g, 14.28 mmol). Themixture was stirred for about 4 hours at 130° C. under nitrogen. Theproduct was then analyzed by an AVATAR 360 FT-IR (“IR”). The sample wasrun in the “Attenuated Total Reflectance mode” placing the sample over aGermanium crystal. The IR spectra showed the almost completedisappearance of the initial anhydride peaks due to the carbonyl groups(peaks at 1859 and 1778 cm-1), and the appearance of carbonyl peaks at1735 and 1704 cm-1 due to the formation of ester and acid respectively.

Other properties of the product were identified as follows:

Solubility in water at 25° C.˜1%.

The scheme below illustrates this synthesis:

Example 2 Reaction Between Alkenylsuccinic Anhydride and AliphaticAlcohol

A reactor was charged with neopentyl alcohol (3.482 g, 33.4 mmol)(Aldrich) and 2-(1-nonenyl) succinic anhydride (15 g, 66.87 mmol)(Aldrich). The mixture was stirred for about 1.5 hours at 130° C. undernitrogen. The product was then analyzed by IR. The sample was run in the“Attenuated Total Reflectance mode” placing the sample over a Germaniumcrystal. The IR spectra showed the almost complete disappearance of theinitial anhydride peaks due to the carbonyl groups (peaks at 1859 and1778 cm-1), and the appearance of carbonyl peaks at 1735 and 1704 cm-1due to the formation of ester and acid respectively.

The product had very limited solubility in water.

The scheme below illustrates this synthesis:

Example 3 Reaction Between Alkenylsuccinic Anhydride andCyclohexylethanol

A reactor was charged with 2-cyclohexylethanol (5.716 g, 44.58 mmol)(Aldrich) and 2-(1-nonenyl) succinic anhydride (10 g, 44.58 mmol)(Aldrich). The mixture was stirred for about 1.75 hours at 130° C. undernitrogen. The product was then analyzed by IR. The sample was run in the“Attenuated Total Reflectance mode” placing the sample over a Germaniumcrystal. The IR spectra showed the almost complete disappearance of theinitial anhydride peaks due to the carbonyl groups (peaks at 1863 and1781 cm-1), and the appearance of carbonyl peaks at 1734 and 1703 cm-1due to the formation of ester and acid respectively.

Other properties of the product were identified as follows:

Solubility in water at 25° C.>1%.

The scheme below illustrates this synthesis:

Example 4 Reaction Between Alkenylsuccinic Anhydride and PolyethyleneGlycol

A reactor was charged with Poly(ethylene glycol), Mn=1000, (6.839 g,6.839 mmol) (Aldrich) and Eka SA 210 brand alkylated succinic anhydride(4.822 g, 13.68 mmol). The Polyethylene glycol was dried before hand ina vacuum oven at about 80° C. for 6 hours. The mixture was stirred forabout 6 hours at 130° C. under nitrogen. The product was then analyzedby IR. The sample was run in the “Attenuated Total Reflectance mode”placing the sample over a Germanium crystal. The IR spectra showed thealmost complete disappearance of the initial anhydride peaks due to thecarbonyl groups (peaks at 1859 and 1782 cm-1), and the appearance ofcarbonyl peaks at 1731 cm-1 due to the formation of ester.

Other properties of the product were identified as follows:

Solubility in water at 25° C.>10%.

Cloud point (1% aqueous, pH>5)>90° C.

Cloud point (1% aqueous, pH<5) 10-40° C.

The scheme below illustrates this synthesis:

Example 5 Reaction Between Alkenylsuccinic Anhydride and PolyethyleneGlycol

A reactor was charged with Poly(ethylene glycol) (Fluka) (molecularweigh 380-420) (12.82 g, 32 mmol) and Eka SA 210 brand alkylatedsuccinic anhydride (22.58 g, 64 mmol). The mixture was stirred for about3 hours at 130° C. under nitrogen. The product was then analyzed by IR.The sample was run in the “Attenuated Total Reflectance mode” placingthe sample over a Germanium crystal. The IR spectra showed the almostcomplete disappearance of the initial anhydride peaks due to thecarbonyl groups (peaks at 1859 and 1778 cm-1), and the appearance ofcarbonyl peaks at 1735 cm-1 due to the formation of ester.

Other properties of the product were identified as follows:

Solubility in water at 25° C.>10%.

Cloud point (1% aqueous, pH>5)>90° C.

The scheme below illustrates this synthesis:

Example 6 Reaction Between an Ethylene Oxide/Propylene Oxide BlockCopolymer and Alkenylsuccinic Anhydride

A reactor was charged with PLURONIC® L64 (BASF) (8.8248 g, 3.04 mmol)and 2-(1-nonenyl) succinic anhydride (1.36 g, 6.09 mmol) (Aldrich). Themixture was stirred for about 6 hours at 130° C. under nitrogen. Theproduct was then analyzed by IR. The sample was run in the “AttenuatedTotal Reflectance mode” placing the sample over a Germanium crystal. TheIR spectra showed the almost complete disappearance of the initialanhydride peaks due to the carbonyl groups (peaks at 1859 and 1782cm-1), and the appearance of carbonyl peaks at 1731 cm-1 due to theformation of ester.

Other properties of the product were identified as follows:

Solubility in water at 25° C.>10%.

Cloud point (1% aqueous, pH>5)>90° C.

The scheme below illustrates this synthesis:

Example 7 Reaction Between Alkenylsuccinic Anhydride and PolyethyleneGlycol Methyl Ether

A reactor was charged with Poly(ethylene glycol)methyl ether (Mn˜550)Aldrich (10 g, 18.18 mmol) and 2-(1-nonenyl) succinic anhydride (4.843g, 18.18 mmol), Aldrich. The mixture was stirred for about 3 hours at130° C. under nitrogen. The product was then analyzed by IR. The samplewas run in the “Attenuated Total Reflectance mode” placing the sampleover a Germanium crystal. The IR spectra showed the almost completedisappearance of the initial anhydride peaks due to the carbonyl groups(peaks at 1855 and 1781 cm-1), and the appearance of carbonyl peaks at1731 cm-1 due to the formation of ester.

Other properties of the product were identified as follows:

Solubility in water at 25° C.>10%.

Cloud point (1% aqueous, pH>5)>90° C.

Cloud point (1% aqueous, pH<5)<90° C.

The scheme below illustrates this synthesis:

Example 8 Reaction Between Polyetheramine and Alkenylsuccinic Anhydride

A reactor was charged with JEFFAMINE® ED-900 (XTJ-501) with MW=900(HUNTSMAN) (10 g, 11.1 mmol), noneyl succinic anhydride (5.919 g, 22.2mmol) (Aldrich) and 15 ml of THF (Aldrich). The mixture was stirred forabout 3 hour at room temperature. Then the solvent was stripped offunder vacuum in a rotary evaporator. The product was analyzed by IR,which showed complete disappearance of the anhydride carbonyl peaks(1859 and 1778 cm-1) and the appearance of the amide and acid carbonylbands (1645 and 1540 for amide I and II respectively, and 1731 cm-1 foracid).

Other properties of the product were identified as follows:

Solubility in water at 25° C.>10%.

Cloud point (1% aqueous, pH>5)>90° C.

The scheme below illustrates this synthesis:

Example 9 Reaction Between an Aliphatic Diacid and a Polyetheramine

Under a nitrogen atmosphere, an oven-dried reactor was charged withanhydrous tetrahydrofurane (15 ml) (Aldrich), adipic acid (0.73 g, 5mmol) Aldrich, JEFFAMINE® M-1000 (XTJ-506) with MW=1000 (HUNTSMAN) (10g, 10 mmol) and dicyclohexylcarbodiimide (Aldrich) (2.269 g, 11 mmol).The mixture was stirred overnight at room temperature. A whiteprecipitate was formed and was removed by vacuum filtration anddischarged. The clear liquid residual that was obtained was stripped offrom solvent under vacuum in the rotary evaporator and analyzed by IR.The IR spectra showed the almost complete disappearance of the initialacid band due to adipic acid (peak at 1692 cm-1), and the appearance ofnew peaks at 1653 and 1540 cm-1, corresponding to amide.

Other properties of the product were identified as follows:

Solubility in water at 25° C.>1%.

Cloud point (1% aqueous)>90° C.

The scheme below illustrates this synthesis:

Example 10 Reaction Between Polyetheramine and Hydrophobic GlycidylEther

A reactor was charged with Glycidyl hexadecyl ether (Aldrich) (5.97 g,20 mmol), JEFFAMINE® ED-2003 (XTJ-502) with MW=2000 (HUNTSMAN, Austin,Tex. 78752, USA) (9 g, 4.5 mmol) and 25 ml of isopropanol. The mixturewas stirred for 5 hours under reflux and under nitrogen. Then thesolvent was stripped off under vacuum. The reaction was monitored by IRfollowing the disappearance of the 915 cm-1 peak (epoxy group) and theappearance of the broad peak at 3500 cm-1 (hydroxy group) The peak at915 cm-1 disappeared almost completely with only very small traces left,indicating that the starting materials have reacted.

Other properties of the product were identified as follows:

Solubility in water at 25° C.˜0.5%.

The scheme below illustrates this synthesis:

Example 11 Reaction Between Polyetheramine and Hydrophobic GlycidylEther

A reactor was charged with Glycidyl hexadecyl ether (Aldrich) (2.9851 g,10 mmol), JEFFAMINE® M-1000 (XTJ-506) with MW=1000 (HUNTSMAN) (10 g, 10mmol) and 25 ml of isopropanol. The mixture was stirred for 5 hoursunder reflux and under nitrogen. Then the solvent was stripped off undervacuum. The reaction was monitored by IR following the disappearance ofthe 915 cm-1 peak (epoxy group) and the appearance of the broad peak at3500 cm-1 (hydroxy group) The peak at 915 cm-1 disappeared almostcompletely, with only very small traces left, indicating that thestarting materials have reacted.

Other properties of the product were identified as follows:

Solubility in water at 25° C.>10%.

Cloud point (1% aqueous) 80-90° C.

The scheme below illustrates this synthesis:

Example 12 Reaction Between Polyetheramine and Hydrophobic GlycidylEther

A reactor was charged with Glycidyl hexadecyl ether (Aldrich) (5.97 g,20 mmol), JEFFAMINE® ED-600 (XTJ-500) with MW=600 (HUNTSMAN) (6 g, 10mmol) and 24 ml of isopropanol. The mixture was stirred for 5 hoursunder reflux and under nitrogen. Then the solvent was stripped off undervacuum. The reaction was monitored by IR following the disappearance ofthe 915 cm-1 peak (epoxy group) and the appearance of the broad peak at3500 cm-1 (hydroxy group) The peak at 915 cm-1 disappeared almostcompletely, with only very small traces left, indicating that thestarting materials have reacted.

Other properties of the product were identified as follows:

Solubility in water at 25° C.>1%.

Cloud point (1% aqueous) 50-57° C.

The scheme below illustrates this synthesis:

Example 13 Reaction Between Polyetheramine and Hydrophobic GlycidylEther

A reactor was charged with Glycidyl hexadecyl ether (Aldrich) (2.985 g,10 mmol), JEFFAMINE® ED-2003 (XTJ-502) with MW=2000 (HUNTSMAN) (10 g, 5mmol) and 26 ml of isopropanol. The mixture was stirred for 5 hoursunder reflux and under nitrogen. Then the solvent was stripped off undervacuum. The reaction was monitored by IR following the disappearance ofthe 915 cm-1 peak (epoxy group) and the appearance of the broad peak at3500 cm-1 (hydroxy group) The peak at 915 cm-1 disappeared almostcompletely, with only very small traces left, indicating that thestarting materials have reacted.

Other properties of the product were identified as follows:

Solubility in water at 25° C.>10%.

Cloud point (1% aqueous) 57-60° C.

The scheme below illustrates this synthesis:

Example 14 Surfactant Solutions Surface Activity

Surfactant molecules were tested for their ability to decrease thesurface tension across the aqueous-organic interface. Interfacialtension (IFT) measurements were conducted using a KSV Sigma 702tensiometer with a Du Nouys ring. Surfactant solutions were prepared at1% by weight in accordance with Examples 4, 8, 13, 3 and 9, and adjustedto neutral pH with 5 M NaOH. Each aqueous surfactant solution was testedinterfacing with air, toluene, Exxon ISOPAR M (blend of C13-C15aliphatics) and light crude oil (API=37.4°). IFT values are reported inTable 1.

TABLE 1 Interfacial Tension Values for Aliphatic-based surfactants. IFTIFT IFT IFT w/Crude w/air w/Toluene w/ISOPAR Oil Surfactant Name [mN/m][mN/m] [mN/m] [mN/m] Deionized Water 71.88 33.12  72.38 a Poly(ethyleneglycol)- 39.10 8.13 6.18 3.69 bis-[3-(2-nonen-1-yl) succinic acid] esterPolyetherdiamine-bis- 43.20 1.50 10.60 7.37 [3-(2-dedecen-1-yl succinicacid] amide N,N′-bis(3-hexadecyl 38.40 6.67 15.95 7.61ether-2-hydroxypropyl) polyetherdiamine 2-(nonen-1-yl)succinic 28.68 <0.01 b 0.09 <0.01 acid mono (2- cyclohexylethyl) esterN(1),N(6)-dipolyether 40.05 12.90  7.58 7.89 hexane diamide aInterfacial tension exceeded maximum device limit of XXX mN/m. bInterfacial tension below minimum device limit of 0.01 mN/m.

As observed in Table 1, the 1% solution of the molecule prepared inaccordance with Example 3 is of particular interest because of its lowIFT values with all three organic liquids. For certain applications,such as EOR, it is desirable to have such low interfacial tensions withcrude oils because EOR surfactant solutions are often used to recovercrude oil that is trapped within the capillaries of rock formations.

Example 15 Surfactant Stability

Application of the synthesized surfactants are tested for their abilityto emulsify different density oil samples while also yielding a stablemixture that does not phase separate. In the experiments listed below, a2 mL sample of heavy oil (API=15.0°) was combined with 2 mL samples of1% by weight surfactant solutions, including a test surfactant solution,and two commercial surfactants. The test surfactant solution wasprepared by dissolving 1.01 grams of the molecule prepared in accordancewith Example 3 in 100 mL of deionized water, and neutralizing it with0.547 grams of 5M NaOH. The mixture was then shaken by hand for 10minutes and set aside. The commercial surfactants Igepal DM-970 andTergitol 15-S-30 were used to form 1% by weight surfactant solutions tocompare with the test surfactant. Deionized water was used as thecontrol. Photographs and phase height measurements were taken at 5, 30,and 60 minutes as well as 24 hours after mixing. Table 2 displays thepercentage of the solution occupied by emulsion phase over time for eachsurfactant (test surfactant and two commercial surfactants). FIG. 1shows the behavior of the emulsion over time, and shows a control samplecontaining DI-water (without surfactant). This example demonstrates thatthe synthesized surfactant of the present invention are capable ofstabilizing heavy oil over long periods of time.

TABLE 2 Phase stabilityof surfactant solutions compared to commercialproducts. % mixture volume occupied by emulsion Surfactant solution 5min 30 min 60 min 1 day Test surfactant (Example 3) 93 79 64 36 IgepalDM-970 21 14 14 14 Tergitol 15-S-30 21 14 14 7 Deionized water control21 14 14 7

Example 16 Surfactant Switchability by pH Variation

Surfactant switchability can be induced by the adjustment of mixture pH.Surfactant solutions that exhibit emulsifying characteristics at neutralpH can be deactivated from surface activity when the pH becomes acidic.This will allow for controlled recovery of oil from an otherwise stableemulsion. A test surfactant was compared to the commercial surfactantTergitol 15-S-7. The surfactant solution was prepared by dissolving themolecule prepared in accordance with Example 3 in deionized water andadjusting the pH to neutral by the addition of 5 M NaOH. Two oilmixtures were prepared for each surfactant solution: initially the twomixtures had neutral pH, but after the vials were agitated and emulsionwas formed, a few drops of HCl 10M was added to one of the vials todecrease the pH to ˜3.

In each case, 2 mL of heavy oil (API=15.0°) was added to 2 mL of 1% byweight surfactant solution, and the vial was agitated to mix thecomponents. Photographs of the vials were taken after 5, 30, 60 minutesand 24 hours after mixing, along with measurements of the height of vialoccupied by water phase and emulsion phase. Table 3 displays thepercentage of the solution occupied by the emulsion phase over time forthe test surfactant solution, the commercial surfactant (Tergitol15-S-7), and a control sample containing deionized-water and oil(without surfactant). The example shows that the surfactants of thisinvention can emulsify-demulsify oil depending on the pH of the mixture.

TABLE 3 Comparison of emulsion stability at neutral and acidic pH. %mixture volume occupied by emulsion Surfactant 30 60 solution Acid pH 5min min min 1 day Test (Example 3) No 9 100 99 93 43 Test (Example 3)yes 1 0 0 0 0 Tergitol 15-S-7 No 6 96 93 86 36 Tergitol 15-S-7 Yes 1 9364 50 29 DI-Water No 6 0 0 0 0 DI-Water Yes 1 0 0 0 0

FIG. 2 shows the behavior of the emulsion with and without acid after 5minutes along with a control sample containing DI-water (withoutsurfactant) and a 1% solution of a commercial surfactant Tergitol15-S-7.

In addition, a 105 mL sample of heavy oil (API=15.0°) was combined with45 mL of a 1% by weight solution of the test surfactant (prepared inaccordance with Example 3), producing a 70:30 oil to water mixture. Themixture was gently stirred until it was observed it achieved a singleliquid phase. Previously, the viscosity of the neat heavy oil sample wasmeasured at 3431 cP using a Brookfield DVIII+Rheometer. The 70:30mixture exhibited a viscosity of 100.2 cP. Next, 1 mL of 10 M HCl wasadded and the mixture was stirred gently, while observing phaseseparation of the oil and water. The oil sample was decanted from thecontainer and obtained the same viscosity measurement as the untreatedheavy oil sample.

Example 17 Removal of Crude Oil from Sand Surfaces

Samples of oil-contaminated sand were prepared by mixing 50/70 mesh sandwith a sample of light crude oil (API=28.6°). 100 grams of sand weremixed with 10 grams of oil using a stir rod, until the solid sand wasthoroughly coated and the sample appeared uniform. A muffle furnace setat 650° C. was used to heat a 5 gram sample of oil-contaminated sand for3 hours to determine the total organic content. Additionally, 1% byweight solutions of molecules prepared in accordance with Example 13 andExample 3 were prepared at neutral pH by the addition of small amountsof 5 M NaOH. Samples were stirred using magnetic stir bars until eachsurfactant was completely dissolved in solution. In a separate 200 mLjar, 150 mL of each surfactant solution was added to 30 grams ofoil-contaminated sand.

After addition of the 1% solution from Example 13, it was observed that,after moderate agitation by shaking, the contaminant crude oil wassignificantly removed from the sand surface. Upon initially shaking thejar, the oil separated from the sand surface and became emulsified inthe aqueous solution. After leaving the jar stationary for approximately5 minutes, the oil remained emulsified in the aqueous phase, leaving aclean, settled layer of sand at the bottom. After approximately 30minutes, slight phase separation began to occur with oil forming on thetop layer of the water phase.

Similarly, 30 grams of oil-contaminated sand (10% by weight) was washedwith 150 mL of a 1% surfactant solution from Example 3. Upon initiallyadding the aqueous solution to the jar, it was immediately observed thatoil droplets began to separate from the sand on the bottom of the jarand rise to the water-air interface. Even with only slight agitation ofthe jar by tipping, nearly all of the contamination on the sand wasremoved. Total oil removal percentages are presented in Table 4.

TABLE 4 Oil Removal from Oily Sand % Oil Solution used remaining in %Oil to wash Oily-sand Recovery by Oily-sand After Wash Washing None9.17% DI Water 7.90% 13.86% 1% Example 13 0.75% 91.81% 1% Example 30.53% 94.19%

Example 18 Reaction Between an Ethylene Oxide/Propylene Oxide BlockCopolymer and Phenyl Succinic Anhydride

A reactor was charged with phenyl succinic anhydride (0.564 g, 10.52mmol) and Pluronic L35 (10 g, 5.26 mmol). The mixture was stirred forabout 4 hours at 130° C. under nitrogen. The product was then analyzedby IR which showed almost complete disappearance of the anhydridecarbonyl peaks (1859 and 1785 cm-1) and the appearance of the ester andacid carbonyl band (1731 cm-1).

Other properties of the product were identified as follows:

Solubility in water at 25° C.>10%.

Cloud point (1% aqueous, pH-8)>100° C.

Cloud point (1% aqueous, pH-2) 60-100° C.

The scheme below illustrates this synthesis:

Example 19 Reaction Between an Ethylene Oxide/Propylene Oxide BlockCopolymer and Phenyl Succinic Anhydride

A reactor was charged with phenyl succinic anhydride (0.9746 g, 18.2mmol) and Pluronic L31 (10 g, 9.1 mmol). The mixture was stirred forabout 2.5 hours at 130° C. under nitrogen. The product was analyzed byIR which showed almost complete disappearance of the anhydride carbonylpeaks (1859 and 1785 cm-1) and the appearance of the ester and acidcarbonyl band (1731 cm-1).

Other properties of the product were identified as follows:

Solubility in water at 25° C.>10%.

Cloud point (1% aqueous, pH-8)<64° C.

The scheme below illustrates this synthesis:

Example 20 Reaction Between an Aromatic Diacid and a Polyetheramine

Under a nitrogen atmosphere, an oven-dried reactor was charged withanhydrous dichloromethane (25 ml), terephthalic acid (0.831 g, 5 mmol),Jeffamine M-1000 brad polyethermonoamine (10 g, 10 mmol) anddicyclohexylcarbodiimide (2.269 g, 11 mmol). The mixture was stirredovernight at room temperature. A white precipitate was formed. Thismaterial through a Buchner funnel. The clear liquid residual that wasobtained was stripped of from solvent under vacuum. The liquid residualproduct was analyzed by IR, which showed that a fraction of the startingterephthalic acid peak was present at 1700 cm-1, and that new amidepeaks appeared at 1653 and 1536 cm-1, consistent with the reactionbetween the aromatic diacid and the polyetheramine proceeded partially.The scheme below illustrates this synthesis:

Example 21 Preparation of secondary amine by reacting a Polyetheramineand Phenyl Glycidyl Ether

A reactor was charged with phenyl glycidyl ether (3 g, 20 mmol),Jeffamine M-1000 brand polyethermonoamine (10 g, 10 mmol) and 25 ml ofisopropanol. The mixture was stirred for 5 hours under reflux and undernitrogen. Then the solvent was stripped off under vacuum.

The reaction was monitored by IR following the disappearance of the 915cm-1 peak (epoxy group) and the appearance of the broad peak at 3500cm-1 (hydroxy group).

Other Properties:

Solubility in water at 25° C.>10%.

Cloud point (1% aqueous) 57-60° C.

The scheme below illustrates this synthesis:

Example 22 Interfacial Tension (IFT) Measurements of Surfactants

Solutions of surfactants, listed in Table 5 below, were dissolved inaqueous solution at 1% by weight. Deionized water was used as thecontrol. Each surfactant was formulated as described above. The pH ofeach solution was adjusted to 9 by the addition of 1 M sodium hydroxide.Using a KSV Sigma 702 tensiometer, the interfacial tension was measuredfor each solution at the interface with air, toluene and Exxon ISOPAR Mfluid. Values are reported in Table 5.

TABLE 5 Interfacial tension measurements for 1% surfactant solutions atthe interface of air, toluene and ISOPAR IFT IFT IFT w/air w/Toluenew/ISOPAR Compound Example [mN/m] [mN/m] [mN/m] 1 Deionized Water Control71.88 33.12 72.38 3 1-[methoxypoly 21 41.50 0.93 5.84 (oxyethylene/oxypropylene)-2- propylamino]-3- phenoxy-2-propanol 4 N,N-bis(3-phenoxy-18 45.77 0.18 7.41 2-hydroxy propyl) polyetheramine

Example 23 Surfactant Properties

A solution prepared in accordance with Example 21 was dissolved intoaqueous solution at 1% by weight and the pH was adjusted to 9 by theaddition of 1 M sodium hydroxide, to form a surfactant solution. 2 mL oflight crude (API gravity index=28) was emulsified at 50:50 volume ratiowith the surfactant solution. The mixture was amply shaken and then leftto sit for one hour. After an hour, no phase separation had occurred.After 2 days of leaving the emulsion to rest, about 1 mL of water hadbeen separated and about 0.5 mL of oil had been separated. An emulsionlayer remained in between the separated water and oil layers.

Example 24 Oily Sand Treatment

30 grams of washed sand (50/70 mesh) was mixed with 3 grams of lightcrude oil (API gravity index=28) by stirring until the oil was evenlydistributed over the surface of the sand. For this experiment, thesurfactant prepared in accordance with Example 21 (Surfactant B) wastested. 150 mL of a 1% surfactant solution was mixed with the oily sandby sealing in a jar and shaking by hand at a moderate pace for 5minutes. The contents of the jar were left to sit for 1 hour and thenthe liquid layer was decanted from the sand. The jar was placed in anoven under vacuum at 100° C. for 3 hours, then cooled to roomtemperature. A sample of the dried sand was weighed and placed in amuffle furnace at 650° C. for 3 hours, then reweighed to determine thetotal remaining weight of hydrocarbon on the sand surface. Table 6summarizes the effect of the surfactant solutions.

TABLE 6 Solution used to % Oil remaining in % Oil Recovery washOily-sand Oily-sand After Wash by Solution None 8.83% Deionized water7.90% 10.54% 1% Surfactant B 1.60% 81.93%

EQUIVALENTS

While specific embodiments of the subject invention have been discussed,the above specification is illustrative and not restrictive. Manyvariations of the invention will become apparent to those skilled in theart upon review of this specification. Unless otherwise indicated, allnumbers expressing quantities of ingredients, reaction conditions, andso forth used in the specification and claims are to be understood asbeing modified in all instances by the term “about.” Accordingly, unlessindicated to the contrary, the numerical parameters set forth herein areapproximations that can vary depending upon the desired propertiessought to be obtained by the present invention.

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims.

What is claimed:
 1. A compound having the Formula:

wherein D is polyethylene glycol.
 2. A method for extracting oil from anoil mixture comprising: (a) adding a compound of claim 1, to an oilmixture, and (b) collecting the oil.
 3. A composition comprising anoil-in-water emulsion and the compound of claim 1, wherein theoil-in-water emulsion comprises petroleum and water.